Search PubMed⌕ Search

Biomedical subjects

T Mosmann

Publications and source records attributed to T Mosmann.

25 records · Page 2Linked to original sources
PubMed1984

Isolation and characterization of a mouse cDNA clone that expresses mast-cell growth-factor activity in monkey cells.

A cDNA sequence coding for mouse mast-cell growth-factor (MCGF) has been cloned from a cDNA library prepared from mRNA derived from a concanavalin A-activated mouse T-cell clone. Cloning was achieved using the pcD vector that permits expression of cDNA inserts in mammalian cells. The DNA sequence codes for a polypeptide of 166 amino acid residues including a putative signal peptide. The supernatant fluid obtained after transfection of COS-7 monkey cells with the pcD-MCGF plasmid had mouse MCGF activity. The MCGF amino acid sequence between amino acids 33 and 41, deduced from the nucleotide sequence of its cDNA, is identical to the NH2-terminal sequence of the mouse lymphokine, interleukin 3, suggesting that MCGF is related to interleukin 3.

Amino Acid Sequence↗
PubMed1983

Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays.

A tetrazolium salt has been used to develop a quantitative colorimetric assay for mammalian cell survival and proliferation. The assay detects living, but not dead cells and the signal generated is dependent on the degree of activation of the cells. This method can therefore be used to measure cytotoxicity, proliferation or activation. The results can be read on a multiwell scanning spectrophotometer (ELISA reader) and show a high degree of precision. No washing steps are used in the assay. The main advantages of the colorimetric assay are its rapidity and precision, and the lack of any radioisotope. We have used the assay to measure proliferative lymphokines, mitogen stimulations and complement-mediated lysis.

Animals↗
PubMed1983

Characterization of polypeptides serologically and structurally related to hexosaminidase in cultured fibroblasts.

Human fibroblasts synthesize several polypeptides that assort into the various forms of hexosaminidase (hex). We report here the occurrence of three newly identified, hexosaminidase-related polypeptides resolved by sodium dodecyl sulfate-poly-acrylamide gel electrophoresis of immunoprecipitates from [35S]methionine-labeled cell extracts. These polypeptides, called band 2 (75,000), band 3 (70,000), and band 4 (63,000), were immunoprecipitated by an antiserum specific to placental hex I2. They are distinct from pre-alpha- (60,000) and pre-beta- (58,000) precursor polypeptides and the alpha- (56,000), beta a- (27,000), and beta b- (27,000) polypeptides of the mature hex A (alpha beta a beta b) and hex B (2[beta a beta b]). When fibroblast extracts were chromatographed on DEAE-Sepharose, bands 2, 3, and 4 were eluted together in fractions before hex A, in a position characteristic of serum and placental hex I2 and serum hex P. This suggests that bands 2, 3, and 4 might represent the polypeptides of a fibroblast hex I. The analysis of partial proteolytic digests of the radioactively labeled polypeptides revealed that bands 2 and 3, pre-beta, and beta a had several peptides in common, suggesting that they are structurally related to each other. However, bands 2, 3, and 4 were present in extracts of Tay-Sachs (pre-alpha and alpha deficiency) and Sandhoff cells (pre-beta, beta a, and beta b deficiency) and appeared later than pre-beta in pulse-chase experiments. These results suggest that bands 2 and 3 occur independently of pre-beta and beta a and are probably specified by different mRNA, whether from the same gene or distinct but homologous genes.

Animals↗
PubMed1982

Arrangement of lambda light chain genes in mutant clones of the MOPC 315 mouse myeloma cells.

The synthesis of lambda light chains and the arrangement of the lambda-chain genes was examined in cells of the mouse myeloma MOPC 315, which is an alpha lambda 2 producer, and in several mutants derived from it. The mutants produce lambda 2 chains only (MOPC 315.26, MOPC 315.34, and MOPC 315.37) or fail to produce alpha and lambda 2 chains (MOPC 315.25 and MOPC 315.36). Messenger RNA from the lambda 2 chain-producing cells directed the synthesis of a lambda 2 chain precursor and a fragment of the lambda 1 chain (lambda 1 F) in a wheat embryo cellfree system, whereas mRNA from the cells that do not produce lambda 2 chains directed the synthesis of lambda 1 F only. DNA from the parental MOPC 315 cells and from the lambda 2 chain-producing cells contained discrete EcoRI restriction fragments coding for rearranged lambda 1 and lambda 23 chain genes and their respective germ-line V and J-C regions. DNA from the no-Ig-producing cells contained fragments coding for the rearranged lambda 1 chain gene and the germ-line V lambda 2 region, but it lacked the sequences coding for the rearranged lambda 2 chain gene and the germ-line V lambda 1 and J-C lambda 1 regions. These results suggest that rearrangements of the lambda 1 and lambda 2 chain genes occur on different chromosomes in MOPC 315 cells and imply that rearrangements of the lambda 1 and lambda 2 chain genes on the same chromosome may be mutually exclusive.

Animals↗
PubMed1975

Synthesis but not secretion of J chain by variant mouse myeloma cells which lose alpha-chain-synthesizing ability.

We have devised a rapid method for obtaining large amounts of J chain from IgA in the ascitic fluid of mice bearing the MOPC 315 tumor. The J chain was released by reduction from the MOPC 315 IgA adsorbed onto a DNP-lysyl-Sepharose column, and was further purified by DEAE Sephadex chromatography. The mouse J chain was characterized as to its electrophoretic mobility, amino acid composition, apparent size, presence in different immunoglobulin classes, and reactivity with an antiserum containing anti-J chain activity. Variant cell lines have been selected from the IgA-producing mouse myeloma cell line MOPC 315. The variants did not synthesize detectable quantities of alpha heavy chains but continued to synthesize and secrete light chains. J chain was synthesized by both parent and variant cell lines but only secreted by the parent cells. It is postulated that J chain synthesis is not dependent on alpha heavy chain synthesis, but that secretion of J chain by MOPC 315 cells occurs only because of its attachment to the Ig1 molecule.

Amino Acids↗
PubMedDate not supplied

Antigen-specific helper factor reacts with antibody to the T-cell receptor.

Antigen-specific helper factor (ASHF), a soluble product of T helper (Th) cells, binds antigen and can induce B-cell and cytotoxic T-lymphocyte (CTL) differentiation. Its relationship to the T-cell surface antigen receptor (TcR) is unknown. Both have MHC-restricted recognition of nominal antigen, thus they may share very similar combining sites. Using monoclonal anti-TcR to immunoprecipitate partially purified ASHF, we have obtained evidence for shared determinants between ASHF and the TcR. Antigen affinity-enriched supernatants of a Th clone, LB19, are functionally active in antigen-specific, help-dependent CTL assays. FPLC anion exchange salt fractions of these supernatants were 125I-labelled and immunoprecipitated with KJ16.133 monoclonal anti-TcR coupled to Sepharose 4B. Precipitates were analysed by SDS-PAGE. We have obtained clear evidence that functionally active Th culture supernatants contain molecules specifically precipitable by anti-TcR antibody.

Animals↗